Brake-control mechanism for concrete mixing and other machines



Feb. 28, 1933. s SHAFER, JR 1,899,167

BRAKE CONTROL MECHANISM FOR CONCRETE MIXING AND OTHER MACHINES FiledFeb. 1, 1927 :s Sheets-Sheet .1

Feb. 28, 1933. s. SHAFER, JR

BRAKE CONTROL MECHANISM FOR CONCRETE MIXING AND OTHER MACHINES FiledFeb. 1, 1927 3 Sheets-Sheet 2 Feb; 28, 1933. 5. SHAFER, JR 1,899,157

BRAKE CONTROL MECHANISM FOR CONCRETE MIXING AND OTHER MACHINES FiledFeb. 1, 1927 3 Sheets-Sheet 3,

Patented Feb. 28,1933 1 rsm mzsnnmm orrmrnwauxnn wrsconsrinassrcnon ennu-3 m; n t

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v i o Application filed February 1,1921? Serial No. 165,171. 1 i p in Inthe operation of concrete mixing Illa- ,land 2 and with thedash'potth'ereof broken chines it is customarytofload therevolvingdrum-: in which concrete is mixedbymeans I i of a pivotedskip that restsupon the ground 1 i 5 to receive itsload .andis then elevated 'to' suchposition that the charge will slide into the interior of the mixingdrum;The movements of the skip are ordinarily controlled by cables that are'connectedwith the skip'and pass to :710 winding, drums, which aredriventhrough gearing connected with a suitable source'of descent of theskip is usually power. The 7 controlled by means of a brake that retardsV the'unwinding'of thecables, this brake being manually controlled, "It'sometimes happens that through inattention or inefficiency of theoperator the skip is allowed :to descend with- -out being controlled bythe brake, and this has resulted in the injury of workmen, im-

7 mediate damage to the-apparatus; andthe entanglementofthe cables, dueto therapid rotation of the drums on which they are sup- 1ported',"which"latter is an almost inevitable resultof too rapid descent of theloaded'skip,

25 andmeans-trouble and delayin properly're-c storing the cables topositions upon thedrums and-perhaps serious injury to the machine ifattempt bemade'to elevat'e theskipfbeiore g v 7 the cables havebeenproperly replaced. i I

My invention has for its object to provide i'autoinatic means, forcontrolling the descent T of the skip in a machine such as described andfor controllingthe movements of apiece of sme e sm y i ed-by e loading sa concrete inlx ng machine, and one embodi- ,Qment thereof isillustrated in the' accom'panying drawings and will be described in thespecification tofollow, .i

it 40 q In th drawlngsFig, 1 isaiside view of a a v concrete -mixingmachine to whichvmy inven- .tion-is app'1ie l 1 a Fig: 2isan end viewofthe same; i a r '-.Fig.;3 isan end @view of the brake contro mechanismdrawn to a largersca'le than Figs.

for "manual control. 1

' mixing machine of well known construction,

in which A represents i. a rotatable drum wherein the concrete ismixed-,B the loading skip pivotall'y supported" on a shaft b mount,

edin 'the fra meworkG of the-machine; The inovementsof the'skip,-fromitslower charge- 3'55 receiving position, represented in fulllines,

to its elevated discharging position, indicated in dotted linesyarecontrolled by cables D whichfare wound'upon drumsld, supported on acrossshaft mounted in the upper part 0 ofth-e-framework C. A largeqwheelEkis" supported onthe same shaft as that carrying the drums d, and tothis is attached a cable Fthat extends to the winding drum G; The drum Gis rotated to'wind the cable "F thereon andelevate the skip to.disch'argingxposition from a powershaft H, through suitable gearing.including a clutch 1,: controlled'by an operatinglever J, thelever-being'adapted L Associated web t winain (1mm 1G is a brake wheelor drum K' with which'enzages a brake 'bandL controlledibya leverM,which islikewise adapted for manualcon- I ,trol. The parts thus far.described-are of well known. construction 18nd, so far as my presentinvention is concernedythey may be I ofthe specific form shown ortheymayi difie'r therefrom quite widely inr-det'ails of constructio'n and inarrangement. 1

Th-eshaft b to whichtheskip is secured is represented as provided with acrank {arm 2, located on'the same side of themac-hine as is" the brakelever M? j Adash-pot- 3 con- J nected with the brakelever, as by apivot45 5' The dash-pot; which may beof usual con-c structiomhasa piston'5 that connected by V 'apiston rod 6 with the crank arm 2, the piviota;connection of these parts being indicated v An air port 8 opens to theexternal atmosphere through the cylinder of the dash-pot on that side ofthe piston 3 that is toward the brake lever. A needle valve 9 isarranged to control the size of this port. It will thus be seen thatthere is interposed a dash-pot between a part that moves as the skip israised and lowered and the brake lever. As the skip is raised todischarging position the crank arm 2 is moved in the direction of thearrow, Fig. 1, moving the piston 5 of the dash-pot downward or in adirection away from the brake lever, and as it so moves air is drawninto the cylinder of the dash-pot through the port 8. As the skip movesslowly as it is elevated from its loading position to that ofdischargethere will be abundant timefor the" cylinder of the dash-pot to fillwith air, through the port 8, without perceptibly opposing the upwardmovement of the skip. After the skip reaches the position to discharge,the driving connection with the power shaft is broken, through themanipulation of the lever J that controls the clutch, and the skip maythen be momentarily held in its elevated position, either by the usualspring 10, or manually by moving the handle M'tO apply the brake. But alight application of the brake is required for this purpose as thecenter of gravity of the skip is so little to one side of the verticalplane that includes the pivot 6. Instead of providing for a short restor dwell ofthe skip in its raised discharging position the apparatus maybe so designed that the skip will begin'its downward movement as soon asthe driving .con-

nection with the power shaft is broken through the manipulation of theclutch. As the skip moves downwardly the shaft 1; is rotated and thepiston 5 is moved upwardly within the cylinder of the dash-pot compress-7 ing the body of air between the piston and the upperend of thecylinder. The pressure thus created, acts upon the cylinder, and throughits pivotal connection 4 with the lever M, upon such'lever, to set thebrake, and the more rapid the descending movement of the skip thegreater the force with which the brake is applied. If the portion of thecylfinder to therear of the piston 5 were closed air tight, it isapparent that the brake would very soon be so tightly set as to hold theskip suspended against further downward movement; but as the port 8allows for a leakage of the air within the cylinder, the pressuretherein is gradually reduced, with a corresponding reduction of'thepressure of the brake upon the drum K and thusthe-brake is keptapplied with just enough pressureto allow the skip to descend safely.

The relations of the Various parts are such that the leakage of airthrough the 'port 8 will be just sufficient to maintain an air pressurewithin the dash-pot 1 that will set the braketo such a degree as willallow the skip vated; the pivoted part returning by to descend at thedesired speed. If it should be found that the descent is too slow theneedle valve 9 will be adjusted to enlarge the port; while on the otherhand if the descent be too rapid the size of the port will be reduced bysuch valve.

I have described means by which the descent of the loading skip isautomatically controlled and this is done through the application of abrake associated with the winding drum of the cable that moves the skip.The lever with which the dash-pot is connected is, as has been stated, alever capable of manualcontrol, and this permits the operator of theapparatus to govern the descent of the skip quite'irrespective oftheautomatic apparatus that has been described,

allowing im either to set the brake, at any point in the, descent of theskip, with a force suflicient to immediately arrest the movementthereof, or to accelerate the. descent of the skipbeyond thespeedcontemplated by'the operation ofthe automatic apparatus.

WhileI have described my invent-ion applied to aconcrete mixing machineit is not,

operated lever for controlling the brake, of.

connections between the moving part and the brakev through which thelatter is automatically controlled by the movements of the former andinaccordance with its speed, the brakebeing manually operableirrespecfive of the automatic operating means.

*2. The combination with a moving pivoted part'of an apparatus, a brakefor controlling its movements and a imanually operated brake lever, Vpivotedpart and the brake leverthrough part moves.

3. The combination with a pivoted part of an apparatus, a cable throughwhich it is elegravity, a brake-for controlling the return movements ofthe said part and a manually operated brake lever, of an arm movablewith the pivoted part and a connection between the said arm and thebrake lever including a dash-pot.

4. The combination with a pivoted movable part of an apparatus, cablesby which it is raised, power-driven winding mechanism for the: cables, abrake'by which the return or lowering movements of the said movable partare controlled and a manuall operated hand lever for the brake, of aera-n arm connected so'as to move with the said movable part andconnections between the said crank of connections'between the said whichthe brake is operated as the pivoted V media? arm and the hrakelever including a dash-pot.

5. The combination witha pivoted. movable part of an apparatus, cablesby which it is moved, power-driven winding mechanism; for the cables, adrum" by which the returnor I lowering movements of the movable part-arecontrolled, and a manually operated hand lever for the brake, of acrankarm movable with the said movable part, a dash-pot having pivotalconnection with thebrakelever; and a. rod carrying the pistonof thedash-pot having pivotal connection with the crank arm, the restrictedairport of thev dash-pot being in that end thereof toward the brake 1lever. V

SAMUEL'NSHIAFER, Y r i

